Field of the Invention
The present invention generally relates to a method for forming a Ti-containing film by plasma enhanced atomic layer deposition (PEALD) using tetrakis(dimethylamino)titanium (TDMAT) and/or tetrakis(diethylamino)titanium (TDEAT).
Description of the Related Art
Ti-based films have been formed for a long time by sputtering method, PVD method, and CVD method, and, for example, TiN films having low sheet resistance have been commercially used as copper-diffusion blocking films. In addition, with recent shrinkage of device nodes, spacer-defined double patterning (SDDP) has gradually started being used as a technology for miniaturization, and TiO and TiN are considered to be good candidates for hard masks for SDDP. For the SDDP hard masks, conformal films having good step coverage are required in view of the nature of the hard masks, and therefore those skilled in the art have used and evaluated TiO- and TiN-based conformal films which are formed by the ALD method which generally provides good step coverage. In particular, TiN generally has difficulty controlling stress and it is likely to become strongly compressive, and thus controlling stress is one of the challenges. Furthermore, due to the miniaturiation of device nodes, it has been difficult to form conformal films having good step coverage by conventional methods such as sputtering method, PVD method, and CVD method, and thus, as an alternative method, a method of forming films having good step coverage and low sheet resistance has come into demand.